This week's top seed is world No. 1 star Novak Djokovic, who will face fellow Serb Dusan Lajovic in the first round on Tuesday. The second seed here is former No. 1 and reigning champion Rafael Nadal, who missed the last few months of the 2014 season due to injuries.

Nadal, who beat France's Gael Monfils in last year's Doha finale, will face German Michael Berrer on Tuesday in his first match since October.